Hi there.
1. What type of material is best for milling circuits from? |
Copper composite. Not sure this is what you're asking. PCB blanks usually come in 1/2, 1 or 2 oz pours. In my experience, I've found 2 oz easier to work with when milling but other thickness work too and can be cheaper.
2. Where to get above material? |
Many places sell these. I buy most of my electronics stuff from
Mouser but try
eBay as well.
3. What size bits/mills to use? I'm assuming carbide is a must for this application. |
This depends mostly on your route lines and how close they are together. End-mills for this purpose can be very small. I cut most of my circuits with a .0312" (0.79mm) endmill. I've been buying my mills from different places but HF has good, resharpened (ie: some previously used) USA made tools that are for this purpose.
NOTE: these are normally $12.99 but here's a trick to get then at $6.49. Go
here, click on "order from printed catalog" and enter item 34640-1RHB. You can't beat qty 50 USA made endmills for $6.49! I have about 500 pieces of these and keep buying more as they are a great deal. All are carbide, top quality, 1/8" shank rated at 60K RPM. You'll see a combination of mills and drills. The last few boxes I've gotten have not had collars on the tools but still is a good deal even if you're not into milling PCBs.
4. Are there any good CAD/CAM programs that make this really easy? |
I use Protel for schematic capturing and PCB manufacturing but many use the free version of
Eagle with good results.
5. What types of feeds/speeds to use? |
I've recently been cutting mine at 15 ipm with 6500 RPM on the spindle. Yes, you don't need to be >25K RPM to mill PCBs. I also have a 45K RPM spindle and frankly, can't tell the difference at that feedrate. I guess I could mill faster with a quicker spindle.
6. How deep do you normally cut? Just enough to break the copper surface, or deeper into your substrate? |
My best work has been when I barely make it below the copper. For a 2 oz copper clad, that comes out to 0.0028" (0.0711mm) deep.
JR